Automatically adjustable condenser cooling apparatus

ABSTRACT

A LOW AMBIENT TEMPERATURE CONTROL FOR AIR COOLED CONDENSERS UTILIZING A MOTOR DRIVEN FAN AND A CONTROL WHICH RAPIDLY RESPONDS TO THE CONDENSER PRESSURE TO ADJUST THE PITCH OF THE FAN BLADES THEREBY PROVIDING A VERY RELIABLE CONTROL OF THE CONDENSER COOLING.

Oct. 12, 1971 DOUGLAS AUTOMATICALLY ADJUSTABLE CONDENSER COOLING APPARATUS Filed July 20, 1970 BE CONDENSER EXCHANGER HEAT COMPRESSOR m T N E V N.

HOWARD IE. DOUGLAS United States Patent 3,611,742 AUTOMATICALLY ADJUSTABLE CONDENSER COOLING APPARATUS Howard E. Douglas, 1396 Barbara Drive, Santa Clara, Calif. 95050 Filed July 20, 1970, Ser. No. 56,452 lint. Cl. F25b 39/04 US. Cl. 62183 4 Claims ABSTRACT OF THE DISCLOSURE A low ambient temperature control for air cooled condensers utilizing a motor driven fan and a control Which rapidly responds to the condenser pressure to adjust the pitch of the fan blades thereby providing a very reliable control of the condenser cooling.

DESCRIPTION OF THE INVENTION This invention relates to a low ambient temperature control for air cooled condensers employing a motor driven fan having fan blades, the pitch of which is adjustable in accordance with the condenser pressure.

An object of this invention is to provide an improved low ambient temperature control for air cooled condensers.

Another object of this invention is to provide an improved fan structure for air cooled condensers having a control responsive to the condenser pressure for controlling the pitch of the fan blades.

Another object of this invention is to provide an im proved fan for the air cooled condenser unit which rapidly responds to the condenser pressure.

Another object of this invention is to provide an improved fan for air cooling condensers which reduces the load on the fan motor when the cooling requirements are low.

Another object of this invention is to provide a cooling unit for air cooled condensers which is readily adaptable to existing systems and which is of low cost and easy to maintain.

Still another object of this invention is to provide an improved motor driven fan adapted to be used with air cooled condensers, said fan being mounted on a hollow shaft which is driven and which is provided with a control that extends through said hollow shaft to adjust the pitch of the fan blades, said control being actuated by an expandable member that is connected to the pressure line extending from the compressor to the condenser so that said control is responsive to the pressure in said line and adjusts the fan blade pitch accordingly.

Other and further objects of this invention will be apparent to those skilled in the art to which it relates from the following specification, claims and drawing in which, briefly:

FIG. 1 is a diagram of a system with which this invention is adapted to be employed;

FIG. 2 is a view of the motor and fan driven thereby showing the motor partially broken away to show the hollow shaft thereof and the fan blade control;

FIG. 3 is a detail view showing the connection of the fan blade control; and

FIG. 4 is a detailed view showing the hollow shaft driven by a pulley and belt arrangement.

Referring to the drawing in detail, reference numeral designates a motor driven compressor of conventional construction having a high pressure line 11 connected thereto and to the condenser 12 which is also of conventional construction. The compressed gas supplied through the line 11 to the condenser 12 is cooled in the condenser and the cooled fluid which may be a liquid is 3,611,742 Patented Oct. 12, 1971 then supplied through line 13 and control device 14 to the heat exchanger 15 which is located in the area to be cooled or refrigerated. A return line 16 is connected between the heat exchanger 15 and the compressor 10.

An auxiliary line 17 is connected between the line 11 and the control device 18 which is provided with an expandable member 18a that is responsive to the pressure in the line 17 to which it is connected. Expandable member 18a may comprise a set of bellows, expandable diaphrams or a piston and cylinder arrangement and it is mechanically coupled to the rod 19. The rod 19 applies pressure through the thrust bearing 20 to the control rod 21 that is positioned inside of the hollow motor shaft 22 of the electric motor 23. The electric motor 23 is provided with an armature 24 that is fixedly attached to the hollow shaft 22 for driving this shaft when the motor is energized from a conventional electric power supply. If desired the hollow shaft 22 instead of forming the shaft of a motor, may be mounted on separate bearings 24a, and it may be provided with a pulley 24b so that it may be driven by a belt 24c from a separate motor.

The fan is provided with a hub 25 that is fixedly attached to the shaft 22 and is rotatable therewith. Several fan blades 26 are attached to the rods 27 by suitable brackets 28 so that the pitch of these blades may be adjusted while the hub 25 and rods 27 are in motion. The rods 27 are fixedly attached to the hub 25 and the outer ends of these rods are provided with enlarged portions 27a which engage the outer brackets 28 and prevent them from sliding off of the rods when the fan is rotating.

The rod 21 which is positioned inside of the hollow motor shaft 22 is provided with a disc 29 which is fixedly attached thereto. One of the ends of the connecting rods 31 are pivotally connected to the disc 29 and the other ends thereof are pivotally connected at 33 to the fan blades 26. The blades 26 are normally held in their fiat position substantially parallel to the disc 29 by pressure applied by spring 32 which is positioned between the shaft 22 and the thrust bearing 20'. One side of the thrust bearing 20 is fixedly attached to the rod 21 so that the pressure of the spring 32 moves the rod 21 inward until the hub of disc 29 attached thereto engages the shaft 22.

When pressure is applied through the line 17 to the expandable member 18a of the pressure-responsive device 18 the member moves the shaft 19, the thrust bearing 20 and shaft 21 thereby moving the hub 29 away from the shaft 22. At the same time the rods 31 turn the fan blades 26 to increase the pitch thereof. When the pitch of the blades 26 is increased, the volume of air moved by the fan through the condenser 12 is increased. Thus, it will be seen that as the pressure in the line 11 connected between the compressor 10 and the condenser 12 increases the pressure-responsive device 18 causes the pitch of the fan blades to be increased so that the volume of air that is moved through the condenser is increased thereby increasing the cooling of the condenser. On the other hand, when the pressure in line 11 to the condenser 12 decreases then the pitch of the blades 26 of the fan is reduced and the volume of air moved through the condenser is also reduced thereby at the same time reducing the load on the fan motor 23. The pressure-responsive device 18 may be adjusted so that it does not adjust the fan blades from a predetermined minimum pitch until the pressure in lines 11 and 17 rises to a predetermined value. After the pressure in lines 11 and 17 rises to the predetermined value and continues to rise, the pitch of the fan blades will increase only as long as the pressure continues to rise until maximum pitch is reached. However, before that point is reached the fan blade pitch can fluctuate either way as the pressure decreases or increases. Thus the device tends to regulate the condenser pressure. Also the load on the motor driving the fan is regulated according to the cooling requirements of the condenser and the motor is not kept running at full load when the cooling requirements are low.

While I have shown and described a preferred form of the invention it will be understood that the invention is capable of variation and modification from the form shown so that the scope thereof should be limited only by the scope of the claims appended hereto.

What I claim is:

1. A low ambient temperature control for an air cooled condenser which is provided with a high fluid pressure line connected thereto, the combination of a hollow shaft, means driving said hollow shaft, a fan fixedly attached to said shaft, said fan being positioned to move air through said condenser when driven by said driving means, said fan having blades with adjustable pitch, means adjusting the pitch of said blades, said means including a rod slidably supported in said hollow shaft and means connecting said rod to said blades, pressureresponsive means connected to said high pressure line and being responsive to the pressure in said line, means connecting said pressure-responsive means to said rod to move said rod in said shaft and adjust the pitch of said fan in accordance with predetermined pressure in said line.

2. A low ambient temperature control for an air cooled condenser which is provided with a high fluid pressure line connected thereto, the combination as set forth in claim 1, further characterized in that one end of said rod extends out of said hollow shaft, said connecting means includes a member attached to said one end of said rod and additional members connected to said member and to said fan blades for increasing the pitch of said blades when said one end of said rod is moved away from said hollow shaft. 7

3. A low ambient temperature control for an air cooled condenser which is provided with a high fluid pressure line connected thereto, the combination as set forth in claim 2, further comprising a hub attached to one end of said shaft adjacent to said one end of said rod and means rotatably supporting said fan blades on said hub.

4. A low ambient temperature control for an air cooled condenser which is provided with a high fluid pressure line connected thereto, the combination as set forth in claim 3, further characterized in that said means connecting said pressure responsive means to said rod comprises a thrust bearing attached to the other end of said rod, said other end of said rod projecting out of the other end of said shaft, and spring means pressing said rod to normally hold said fan blades at minimum pitch.

References Cited UNITED STATES PATENTS 2,952,991 9/1960 St. Pierre 62CP 3,402,565 9/1968 Maynard 62183 3,469,413 9/1969 Miner 62183 MEYER PERLIN, Primary Examiner U.S. Cl. X.R. 

